In your example, are you saying that a person carrying the virus will infect only 2 others REGARDLESS of how many people are exposed to him? Or are you saying that given "shelter in place and social distancing" rules in place, the "average" infection rate is 2 infected for each carrier because the carrier will only come into contact with X number of vulnerable (i.e., non-immune) people before they recover and are no longer carriers?
And are you assuming that people who recover from the virus are now immune (this has not yet been established in fact IIRC. There have been situations where the virus has recurred a 2nd time in people who have recovered from a 1st bout)?
Thx again for helping me understand this.
R0 is a measure of expected community spread for each person that gets a virus. The common flu has an R0 of about 1.3, which is to say that each person that gets the flu will infect 1.3 people (in the winter time, R0 falls off significantly in the summer as most viruses don't like heat). Depending on the R0 level, once you reach 50-70% of the population is immune, community spread is nearly impossible for most viruses as the spread drops significantly through basic statistics (ie R0 of 1.5 at 50% pop would be 0.75 and would die out, r0 at 3 at 70% is 0.9 and dies out). The higher the R0, the higher % of population that you need to be immune (60-80%). Once R0 goes below zero, it begins to die. However, if R0 goes below zero due to non-natural supression measures like we are doing, as soon as you stop those supression measures, the R0 returns to its original pace (likely 2.5-3 for this virus) and off to the races again.
R0 can vary based on transmission type, heat, humidity and other factors (sanitation, etc)